Having set required_roles on the table, the button did not
disappear, but clicking on it no longer opened the window with the
table, only an error message in the JavaScript console:

TypeError:Lino.ledger.DebtsByPartner.gridisundefined

Explanation: the button was rendered since it did not inherit the
requirements.

I noticed that Lino still declared its development status as “beta”.
It is of course a subjective decision, but for me “beta” is
definitively not true any more. Changed it to Stable and released the
good news to PyPI as version 1.6.19.
Also for Lino Welfare.